U.S. patent number 7,506,442 [Application Number 11/423,982] was granted by the patent office on 2009-03-24 for method of fabricating inkjet printhead.
This patent grant is currently assigned to Samsung Electronics Co., Ltd. Invention is credited to Hyung Choi, Dong-sik Shim.
United States Patent |
7,506,442 |
Shim , et al. |
March 24, 2009 |
Method of fabricating inkjet printhead
Abstract
A method of fabricating an inkjet printhead. The method of
fabricating an inkjet printhead includes sequentially forming an
insulating layer, a heater, and an electrode on a substrate and
forming a passivation layer on the insulating layer to cover the
heater and the electrode; forming a trench that exposes the
substrate by sequentially etching the passivation layer and the
insulating layer; forming a sacrificial layer to form an ink
chamber on the passivation layer to fill the trench; forming a seed
layer to provide a plating on the sacrificial layer and the
passivation layer; forming a nozzle mold on the seed layer
positioned over the heater; forming a plating layer on the seed
layer to a predetermined thickness; forming an ink feed hole by
etching a rear surface of the substrate to expose the sacrificial
layer which is filled in the trench; forming a nozzle by
sequentially removing the nozzle mold and the seed layer positioned
under the nozzle mold; and forming the ink chamber by removing the
sacrificial layer which is exposed by the nozzle and the ink feed
hole.
Inventors: |
Shim; Dong-sik (Suwon-si,
KR), Choi; Hyung (Seongnam-si, KR) |
Assignee: |
Samsung Electronics Co., Ltd
(Suwon-si, KR)
|
Family
ID: |
38138229 |
Appl.
No.: |
11/423,982 |
Filed: |
June 14, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070131648 A1 |
Jun 14, 2007 |
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Foreign Application Priority Data
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Dec 8, 2005 [KR] |
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10-2005-0119252 |
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Current U.S.
Class: |
29/890.1; 29/830;
29/611; 29/831; 29/832; 216/27 |
Current CPC
Class: |
B41J
2/1631 (20130101); B41J 2/1639 (20130101); B41J
2/14137 (20130101); B41J 2/1626 (20130101); B41J
2/1603 (20130101); B41J 2/14129 (20130101); B41J
2/1643 (20130101); Y10T 29/49128 (20150115); Y10T
29/4913 (20150115); Y10T 29/49126 (20150115); Y10T
29/49083 (20150115); Y10T 29/49401 (20150115) |
Current International
Class: |
B23P
17/00 (20060101); G01D 15/00 (20060101) |
Field of
Search: |
;29/890.1,611,830,831,832 ;216/27,55,57 ;347/65,62,66,55,56 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bryant; David P
Assistant Examiner: Nguyen; Tai
Attorney, Agent or Firm: Stanzione & Kim, LLP
Claims
What is claimed is:
1. A method of fabricating an inkjet printhead comprising:
sequentially forming an insulating layer, a heater, and an
electrode on a substrate, and forming a passivation layer on the
insulating layer to cover the heater and the electrode; forming a
trench that exposes the substrate by sequentially etching the
passivation layer and the insulating layer; forming a sacrificial
layer to form an ink chamber on the passivation layer to fill the
trench; forming a seed layer to provide a plating on the
sacrificial layer and the passivation layer; forming a nozzle mold
on the seed layer positioned over the heater; forming a plating
layer on the seed layer to a predetermined thickness; forming an
ink feed hole by etching a rear surface of the substrate to expose
the sacrificial layer filled in the trench; forming a nozzle by
sequentially removing the nozzle mold and the seed layer positioned
under the nozzle mold; and forming the ink chamber by removing the
sacrificial layer exposed by the nozzle and the ink feed hole.
2. The method of claim 1, wherein the substrate is made of
silicon.
3. The method of claim 1, wherein the insulating layer is made of
silicon oxide.
4. The method of claim 1, wherein the heater is formed by
depositing a heating resistor on a top surface of the insulating
layer and patterning the heating resistor.
5. The method of claim 1, wherein the electrode is formed by
depositing a conductive metal on a top surface of the heater and
patterning the metal.
6. The method of claim 1, wherein the passivation layer is made of
silicon oxide and silicon nitride.
7. The method of claim 1, further comprising: after the forming of
the passivation layer, forming an anti-cavitation layer on a top
surface of the passivation layer that forms the bottom of the ink
chamber.
8. The method of claim 7, wherein the anti-cavitation layer is made
of tantalum (Ta).
9. The method of claim 1, wherein the sacrificial layer is formed
by coating a predetermined material on the passivation layer and
patterning the material in a shape of the ink chamber.
10. The method of claim 9, wherein the sacrificial layer is formed
of a photoresist or a photosensitive polymer.
11. The method of claim 1, wherein the seed layer is made of at
least one metal selected from the group consisting of copper, gold,
nickel, titanium, and chrome.
12. The method of claim 11, wherein the plating layer is made of at
least one metal selected from the group consisting of copper, gold,
and nickel.
13. The method of claim 1, wherein the plating layer is formed by
electroplating.
14. The method of claim 1, wherein the nozzle mold is made of a
photoresist or a photosensitive polymer.
15. The method of claim 1, wherein the nozzle mold has a cross
section tapering upward.
16. The method of claim 1, wherein the seed layer is formed by
depositing a predetermined metal on the surface of the sacrificial
layer.
17. The method of claim 16, wherein the seed layer is deposited by
a sputtering method.
18. A method of fabricating an inkjet printhead, comprising:
forming a sacrificial layer over a thermal heating device of the
inkjet printhead to form an ink chamber; forming a seed layer to
provide plating on the sacrificial layer and thermal heating
device; forming a nozzle mold on the seed layer positioned over the
thermal heating device; forming a plating layer on the seed layer
to a predetermined thickness; forming an ink feed hole by etching a
rear surface of the thermal heating device to expose the
sacrificial layer; forming a nozzle by sequentially removing the
nozzle mold and the seed layer positioned under the nozzle mold;
and forming the ink chamber by removing the sacrificial layer
exposed by the nozzle and the ink feed hole.
19. The method of claim 18, wherein the seed layer is formed by
depositing a predetermined metal on the surface of the sacrificial
layer.
20. The method of claim 18, wherein the plating layer comprises a
nozzle layer and a chamber layer formed during a single
process.
21. A method of fabricating an inkjet printhead, comprising:
forming a sacrificial layer over a thermal heating device including
heaters of the inkjet printhead to form an ink chamber; forming a
nozzle mold on the sacrificial layer and above each heater; forming
a plating layer on the sacrificial layer and along sides of each
nozzle mold to a predetermined thickness; forming an ink feed hole
by etching a rear surface of the thermal heating device to expose
the sacrificial layer; forming nozzles by sequentially removing
each nozzle mold; and forming the ink chamber by removing the
sacrificial layer exposed by the nozzles and the ink feed hole.
22. The method of claim 21, wherein the forming of the nozzle mold
comprises: forming a seed layer over the sacrificial layer to
provide plating on the sacrificial layer and thermal heating
device; and forming the nozzle mold over the seed layer and above
each heater.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Patent Application
No. 10-2005-0119252, filed on Dec. 8, 2005, in the Korean
Intellectual Property Office, the disclosure of which is
incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present general inventive concept relates to a method of
fabricating an inkjet printhead, and more particularly, to a method
of fabricating an inkjet printhead using a simple process.
2. Description of the Related Art
An inkjet printhead is an apparatus that ejects minute ink droplets
on desired positions of recording paper in order to print
predetermined color images. Inkjet printheads are categorized into
two types according to the ink droplet ejection mechanism thereof.
The first one is a thermal inkjet printhead that ejects ink
droplets due to an expansion force of ink bubbles generated by
thermal energy. The other one is a piezoelectric inkjet printhead
that ejects ink droplets by a pressure applied to ink due to the
deformation of a piezoelectric body.
The ink droplet ejection mechanism of the thermal inkjet printhead
is as follows. When a current flows through a heater made of a
heating resistor, the heater is heated and ink near the heater in
an ink chamber is instantaneously heated up to about 300.degree. C.
Accordingly, ink bubbles are generated by ink evaporation, and the
generated bubbles are expanded to exert a pressure on the ink
filled in the ink chamber. Thereafter, an ink droplet is ejected
through a nozzle out of the ink chamber.
FIG. 1 is a schematic cross-sectional view of a conventional
thermal inkjet printhead. Referring to FIG. 1, the conventional
inkjet printhead includes a substrate 10 on which a plurality of
material layers are formed, a chamber layer 20 stacked on the
substrate 10, and a nozzle layer 30 stacked on the chamber layer
20. An ink chamber 22 filled with ink to be ejected is formed in
the chamber layer 20 and a nozzle 32, through which ink is ejected,
is formed in the nozzle layer 30. In addition, the substrate 10 has
an ink feed hole 11 to supply ink to the ink chamber 22.
A typical silicon substrate is used as the substrate 110. An
insulating layer 12 for insulation between a heater 13 and the
substrate 10 is formed on the substrate 10. The insulating layer 12
is typically made of silicon oxide. The heater 13 is formed on the
insulating layer 12 to heat the ink of the ink chamber 22 and
generate bubbles. An electrode 14 is formed on the heater 13 to
apply current to the heater 13. A passivation layer 15 is formed on
the heater 13 and the electrode 14 to protect the heater 13 and the
electrode 14. The passivation layer 15 is typically made of silicon
oxide or silicon nitride. An anti-cavitation layer 16 is formed on
the passivation layer 15. The anti-cavitation layer 16 protects the
heater 13 from a cavitation force generated when the bubbles vanish
and is typically made of tantalum (Ta).
FIGS. 2A through 2D illustrate a conventional method of fabricating
the inkjet printhead of FIG. 1. Referring to FIG. 2A, an insulating
layer 12 is formed on a substrate 10 and a heater 13 and an
electrode 14 are sequentially formed on the insulating layer 12.
Then a passivation layer 15 is formed on the insulating layer 12 to
cover the heater 13 and the electrode 14 and an anti-cavitation
layer 16 is formed on the passivation layer 15. Next, the
passivation layer 15 and the insulating layer 12 are sequentially
etched, and thus a trench 17 that exposes a surface of the
substrate 10 is formed. Then, referring to FIG. 2B, a predetermined
material is coated on the structure illustrated in FIG. 2A and is
patterned to form a chamber layer 20, which includes an ink chamber
22 as illustrated in FIG. 1. Then, a sacrificial layer 25 is formed
to fill the ink chamber 22 and the trench 17, and a top surface of
the sacrificial layer 25 is planarized using a chemical mechanical
polishing (CMP) method. Next, referring to FIG. 2C, a predetermined
material is coated on the top surface of the sacrificial layer 25
and the chamber layer 20 and is patterned, and thus a nozzle layer
30 which includes a nozzle 32 is formed. Next, referring to FIG.
2D, a rear surface of the substrate 10 is etched such that the
sacrificial layer 25 is exposed, and thus an ink feed hole 11 is
formed. Then the sacrificial layer 25, which is exposed by the ink
feed hole 11 and the nozzle 32 is removed, and thus the ink chamber
22 is formed.
However, in the above described method of fabricating an inkjet
printhead, several patterning processes are required and the
thickness of the chamber layer 20 cannot be easily obtained as
desired using the CMP.
SUMMARY OF THE INVENTION
The present general inventive concept provides method of
fabricating an inkjet printhead using a simple process.
Additional aspects and advantages of the present general inventive
concept will be set forth in part in the description which follows
and, in part, will be obvious from the description, or may be
learned by practice of the general inventive concept.
The foregoing and/or other aspects and utilities of the present
general inventive concept are achieved by providing a method of
fabricating an inkjet printhead including sequentially forming an
insulating layer, a heater, and an electrode on a substrate, and
forming a passivation layer on the insulating layer to cover the
heater and the electrode, forming a trench that exposes the
substrate by sequentially etching the passivation layer and the
insulating layer, forming a sacrificial layer to form an ink
chamber on the passivation layer to fill the trench, forming a seed
layer to provide a plating on the sacrificial layer and the
passivation layer, forming a nozzle mold on the seed layer
positioned over the heater, forming a plating layer on the seed
layer to a predetermined thickness; forming an ink feed hole by
etching a rear surface of the substrate to expose the sacrificial
layer filled in the trench, forming a nozzle by sequentially
removing the nozzle mold and the seed layer positioned under the
nozzle mold, and forming the ink chamber by removing the
sacrificial layer exposed by the nozzle and the ink feed hole.
The substrate may be made of silicon, and the insulating layer may
be made of silicon oxide.
The heater may be formed by depositing a heating resistor on a top
surface of the insulating layer and patterning the heating
resistor. The electrode may be formed by depositing a conductive
metal on a top surface of the heater and patterning the metal.
The passivation layer may be made of silicon oxide and silicon
nitride.
After the forming of the passivation layer, forming an
anti-cavitation layer on a top surface of the passivation layer
that forms the bottom of the ink chamber may be further included.
The anti-cavitation layer may be made of tantalum (Ta).
The sacrificial layer may be formed by coating a predetermined
material on the passivation layer and patterning the material in a
shape of the ink chamber. The sacrificial layer may be formed of a
photoresist or a photosensitive polymer.
The seed layer may be made of at least one metal selected from the
group consisting of copper, gold, nickel, titanium, and chrome. The
plating layer may be made of at least one metal selected from the
group consisting of copper, gold, and nickel.
The plating layer may be formed by electroplating.
The nozzle mold may be made of a photoresist or a photosensitive
polymer. The nozzle mold may have a cross section tapering
upward.
The foregoing and/or other aspects and utilities of the present
general inventive concept are achieved by providing a method of
fabricating an inkjet printhead comprising forming a sacrificial
layer over a thermal heating device of the inkjet printhead to form
an ink chamber, forming a seed layer to provide plating on the
sacrificial layer and thermal heating device, forming a nozzle mold
on the seed layer positioned over the thermal heating device,
forming a plating layer on the seed layer to a predetermined
thickness, forming an ink feed hole by etching a rear surface of
the thermal heating device to expose the sacrificial layer, forming
a nozzle by sequentially removing the nozzle mold and the seed
layer positioned under the nozzle mold, and forming the ink chamber
by removing the sacrificial layer exposed by the nozzle and the ink
feed hole.
The foregoing and/or other aspects and utilities of the present
general inventive concept are achieved by providing a method of
fabricating an inkjet printhead, comprising forming a sacrificial
layer over a thermal heating device including heaters of the inkjet
printhead to form an ink chamber, forming a nozzle mold on the
sacrificial layer and above each heater, forming a plating layer on
the sacrificial layer and along sides of each nozzle mold to a
predetermined thickness, forming an ink feed hole by etching a rear
surface of the thermal heating device to expose the sacrificial
layer, forming nozzles by sequentially removing each nozzle mold,
and forming the ink chamber by removing the sacrificial layer
exposed by the nozzles and the ink feed hole.
BRIEF DESCRIPTION OF THE DRAWINGS
These and/or other aspects and advantages of the present general
inventive concept will become apparent and more readily appreciated
from the following description of the embodiments, taken in
conjunction with the accompanying drawings of which:
FIG. 1 is a schematic view of a conventional inkjet printhead;
FIGS. 2A through 2D illustrate a conventional method of fabricating
the inkjet printhead of FIG. 1; and
FIGS. 3A through 3H illustrate a method of fabricating an inkjet
printhead according to an embodiment of the present general
inventive concept.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the embodiments of the
present general inventive concept, examples of which are
illustrated in the accompanying drawings, wherein like reference
numerals refer to the like elements throughout. The embodiments are
described below in order to explain the present general inventive
concept by referring to the figures.
FIGS. 3A through 3H illustrate a method of fabricating an inkjet
printhead according to an embodiment of the present general
inventive concept. Referring to FIG. 3A, first, a substrate 110 is
provided. The substrate 110 may be typically a silicon substrate.
An insulating layer 112 is formed to a predetermined thickness on a
top surface of the substrate 110. The insulating layer 112
insulates a heater 113 from the substrate 110 thermally and
electrically and may be typically be made of silicon oxide. The
heater 113 that heats the ink to generate bubbles is formed on the
insulating layer 112. The heater 113 may be made by depositing a
heating resistor made of tantalum-aluminum alloy, tantalum nitride,
titanium nitride, or tungsten silicide and patterning the heating
resistor in a predetermined shape. An electrode 114 is formed on
the heater 113 to apply current to the heater 113. The electrode
114 may be formed by depositing a metal having good electric
conductivity like aluminum, aluminum alloy, gold, or silver and
patterning the metal to a predetermined shape. A passivation layer
115 is formed on the insulating layer 112 to cover the heater 113
and the electrode 114. The passivation layer 115 protects the
heater 113 and the electrode 114 from oxidization or corrosion when
they contact the ink and may be typically made of silicon oxide or
silicon nitride. An anti-cavitation layer 116 is further formed on
a top surface of the passivation layer 115 that forms the bottom of
the ink chamber 122. The anti-cavitation layer 116 protects the
heater 113 from a cavitation force generated when the bubbles
vanish and may be made of tantalum. Then, a trench 117, which
exposes a top surface of the substrate 110, is formed by
sequentially etching the passivation layer 115 and the insulating
layer 112. The trench 117 is formed in the upper position of an ink
feed hole 111 shown in FIG. 3H, which will be described later.
Referring to FIG. 3B, a sacrificial layer 125 is formed on the
passivation layer 115 to fill the trench 117 to a predetermined
thickness. The sacrificial layer 125 is formed by coating a
predetermined material, for example, a photoresist or
photosensitive polymer, on the passivation layer 115 and patterning
the material in a predetermined shape. The sacrificial layer 125 is
removed later to form an ink chamber 122 shown in FIG. 3H, and thus
the sacrificial layer 125 has a shape of the ink chamber 122.
Accordingly, the ink chamber 122 can be obtained with a desired
height by controlling the thickness of the sacrificial layer
125.
Referring to FIG. 3C, a seed layer 126 to provide plating is formed
on the entire surface of the result of FIG. 3B. The seed layer 126
is formed by depositing a predetermined metal on the surface of the
sacrificial layer 125 and the passivation layer 115 using a
sputtering method. The seed layer 126 may be formed of at least one
metal selected from the group consisting of copper, gold, nickel,
titanium, and chrome.
Next, referring to FIG. 3D, a nozzle mold 135 is formed on the seed
layer 126 positioned over the heater 113 to a predetermined height.
The nozzle mold 135 can be formed by coating a predetermined
material, for example, a photoresist or a photosensitive polymer,
and patterning the material in a predetermined shape. The nozzle
mold 135 is removed later to form a nozzle 132 illustrated in FIG.
3H, and thus the nozzle mold 135 is formed in the shape of a nozzle
132. The nozzle mold 135 may have a cross section tapering
upward.
Next, referring to FIG. 3E, when a predetermined metal is plated on
the seed layer 126, a plating layer 140 incorporating a chamber
layer 140a and a nozzle layer 140b is formed. That is, the plating
layer 140 formed on the passivation layer 115 functions as a
chamber layer 140a and the plating layer 140 formed on the
sacrificial layer 125 functions as a nozzle layer 140b. The plating
layer 140 may be formed of a metal having good thermal conductivity
to efficiently dissipate heat generated in the heater 113 to the
outside. In detail, the plating layer 140 may be formed of at least
one metal selected from the group consisting of copper, gold, and
nickel. The plating layer 140 may be formed using an electroplating
method. The electroplating process is completed when the plating
layer 140 is formed at a height lower than the height of the nozzle
mold 135 and when a desired outlet cross section of the nozzle 132
is formed. Accordingly, the nozzle 132 can be obtained with a
desired height by controlling the thickness of the plating layer
140.
Next, referring to FIG. 3F, an ink feed hole 111 to supply ink is
formed by etching the substrate 110. In detail, the ink feed hole
111 is formed by wet etching or dry etching a rear substrate of the
substrate 110 until the sacrificial layer 125 filled in the trench
117 is exposed. Next, referring to FIG. 3G, when the nozzle mold
135 and the seed layer 126 formed under the nozzle mold 135 is
sequentially etched and removed, the nozzle 132 through which ink
is ejected is formed. A top surface of the sacrificial layer 125 is
exposed through the nozzle 132. The nozzle 132 can be formed before
the ink feed hole 111 is formed.
Finally, referring to FIG. 3H, the sacrificial layer 125, which is
exposed through the ink feed hole 111 and the nozzle 132, is etched
and removed, and thus an ink chamber 122 is formed. Thus the inkjet
printhead is completed.
As described above, the present general inventive concept can form
a plating layer as a single body including a chamber layer and a
nozzle layer. Thus, the inkjet printhead can be fabricated in a
simple process. In addition, the thickness of the sacrificial layer
and the plating layer are controlled to obtain an ink chamber and a
nozzle of a desired size. Also, since the plating layer is made of
a metal having good thermal conductivity, the heat generated by the
heater can be efficiently dissipated to the outside.
The general inventive concept may, however, be embodied in many
different forms and should not be construed as being limited to the
embodiments set forth herein; rather, these embodiments are
provided so that this disclosure will be thorough and complete, and
will fully convey the concept of the inventive concept to those
skilled in the art. For example, it will also be understood that
when a layer is referred to as being "on" another layer or a
substrate, it can be directly on the other layer or the substrate,
or intervening layers may also be present. The components of the
inkjet printhead according to the present general inventive concept
may be made of different materials from those described in the
current embodiments. Also, the sequence of stages of the method of
fabricating the inkjet printhead may vary from the embodiments of
the present general inventive concept. Therefore, the spirit and
scope of the present general inventive concept should be defined by
the following claims.
* * * * *